This invention relates to GaAs devices and, more particularly, to the reduction of surface recombination current in such devices.
In the area of Group III-V compound semiconductors recent investigation of the current-voltage behavior of Al.sub.x Ga.sub.1-x As--Al.sub.y Ga.sub.1-y As--Al.sub.x Ga.sub.1-x As (0.ltoreq.y&lt;x), double heterostructure, p-n junction devices has shown that surface recombination is responsible for the observed 2kT current. This surface recombination current is due to nonradiative electron-hole recombination in the surface depletion region at the junction perimeter. Earlier studies of surface current had been concerned with GaP.sub.0.4 As.sub.0.6 and GaP light-emitting diodes where the surface current was also found to be the dominant 2kT current. Etching the GaP surface in a CF.sub.3 plasma did reduce the surface current. However, desorption of F resulted in reversion to the etched surface values. In silicon technology, on the other hand, growth of SiO.sub.2 on Si can greatly reduce the surface recombination current. However, surface chemical treatment or the growth of native oxides, SiO.sub.2 or silicon nitride on GaAs has not been helpful, and the reduction of the surface recombination current on GaAs has eluded solution.